The Russian claim to the region, made Thursday, is based on international law that sets a 200-mile (322-kilometer) territorial limit stretching from the coast into open waters. This limit can be expanded if a country's continental shelf extends further out to sea.

Since 2001 Russian officials have been arguing that an undersea formation called the Lomonosov Ridge is part of Siberia's shelf, and that the country is therefore entitled to sole rights to the ridge and the nearby seabed.

Still, the Russians acknowledge that planting the flag was a purely symbolic act.

"It means nothing" from a legal standpoint, Viktor Posyolov, deputy director of Russia's Institute of World Ocean Geology and Mineral Resources, told the Associated Press several days before the dive.

And Ted McDorman, a law professor at the University of Victoria in British Columbia, told National Geographic News that "what the Russians have done is good politics, but it doesn't affect the legal situation one way or the other."